Java OCA OCP Practice Question 2629

Question

Given: 

2. import java.util.*;  
3. public class Vinegar {  
4.   public static void main(String[] args) {  
5.     Set<Integer> mySet = new HashSet<Integer>();  
6.     do1(mySet, "0");  do1(mySet, "a");  
7.     do2(mySet, "0");  do2(mySet, "a");  
8.   }  //from  ww  w . j a  v a2 s.  c  om
9.   public static void do1(Set s, String st) {  
10.     s.add(st);  
11.     s.add(Integer.parseInt(st));  
12.   }  
13.   public static void do2(Set<Integer> s, String st) {  
14.     s.add(st);  
15.     s.add(Integer.parseInt(st));  
16. } }

Which are true? (Choose all that apply.)

  • A. Compilation succeeds.
  • B. Compilation fails due to an error on line 6.
  • C. Compilation fails due to an error on line 13.
  • D. Compilation fails due to an error on line 14.
  • E. Compilation fails due to an error on line 15.
  • F. If only the line(s) of code that don't compile are removed, the code will run without exception.
  • G. If only the line(s) of code that don't compile are removed, the code will throw an exception.


H:Note

D and G are correct.

It's legal to pass a generic collection to a method that's expecting a non-generic collection.

In do2(), the compiler knows that "s" can contain only Integers and that st is a String.

If this line of code is removed, the parseInt() invocation will throw a NumberFormatException when it is passed "a".




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